A previous post in March 2012, Meditation and Neuroplasticity, outlined research about meditation causing changes in the brain, including new brain cells, axons, dendrites and synapses. These studies showed dramatic brain alterations for all of the major traditions of meditation. A brief summary of that previous research follows.
This post will look at the most recent studies that continue to show new effects of meditation on the brain, as well as new applications.
Some of the information summarized in the previous post appeared in a recent review article in the journal Nature Neuroscience. This article additionally describes that severe stress causes increase in some of the regions of the amygdala, (emotional center related to fear) and decrease in regions of the hippocampus (memory and learning), and pre frontal cortex (decision-making). It notes that meditation counteracts these stress related brain changes. Meditation decreases anxiety and fear, and increases memory and cognitive abilities.
This Neuroscience review reported additionally that compassion meditation (summarized in previous post and below) increased gamma oscillations and synchrony, as well as increased activity in brain regions related to empathy. It also emphasized that changes in the brain from mindfulness meditation can occur in just eight weeks.
The article raised the question whether meditation research is complicated by the fact that changes in the brain could also be from daydreaming, and self-reflection. Daydreaming has been recently linked to creativity (see research and discussion below) and self-reflection might also cause brain changes. Social learning in children, including self-reflection, significantly helped academic achievement.
Brief Summary of Previous Meditation Post
The previously described brain changes for three major types of meditation are:
Compassion: In meditation emphasizing a focus on compassion and “loving-kindness” there was increased concentration. There was also increased activity in frontal brain regions (positive emotions and self control) and thalamus (filters sensory- motor signals), and a decrease in the parietal region (visual and spatial).
Mindfulness: Mindfulness meditation showed increased neurons and connections in right frontal cortex, (concentration), insula (emotions) and right parietal and temporal (sight and sound). It showed a decrease in amygdala (stress), and increase in hippocampus (memory)
Transcendental: Transcendental meditation showed more activity in frontal and parietal (attention), and decrease in thalamus, (sensory) and basal ganglia (choosing actions). The brain waves showed increased coherence and more synchronous oscillations throughout the brain.
Default Network: In all types of meditation a very important finding was that the Default Mode Network (DMN) was changed, briefly in novice meditators and permanently in experienced meditators. The DMN is the part of the brain that operates with non-focused internal thought and daydreaming (memories, future planning, wondering, thinking about others). This new default network caused by meditation now included new brain centers (dorsal anterior cingulate and dorsolateral prefrontal cortex) and was associated with increased control of behavior and thought.
Basically, meditation of all types increased focus and self-monitoring of thought and emotion.
Wide Range of New Research
As the research into meditation has expanded, there are new findings in brain connectivity, neuroplasticity (brain changes and brain region growth), multitasking, and emotional monitoring. Other research has focused on the specific uses of meditation in cancer, cardiovascular disease, depression, and war related stress.
As these new results are incorporated into brain science, a broad question arises about the relation of meditation, daydreaming, sleep, physical exercise and creativity. These are discussed below.
General Brain Changes with Meditation
Gyri in the cortex are the folded regions of the cortex that allow for increased complexity and increased connectivity of the neurons. A recent study showed that with all of the different meditation techniques there are increased folding of the cortex, that is, increased “gyrification.” Significantly, the longer people had practiced the various forms of meditation, the more this effect of increased cortical surface area was evident. This correlates with increase brain effectiveness.
Increased Axon Density and Myelin
A study using advanced diffusion tensor fMRI showed that one month of Chinese mindfulness training, called IBMT (Integrative body-mind training) increased the density of axons, which means more ability to signal and more connectivity (see post on Connectivity). These changes in the neurons of the anterior cingulate, a center for focus, attention, concentration, and self-regulation, also included an increase in myelin (myelin surrounds mature neurons and increases the speed of transmission of the signal). The increase in axons occurred after two weeks, and the increased myelin in one month. In early development axons also develop first, followed later by myelin.
This study of Chinese mindfulness meditation also found decrease in stress, measured by hormones in the blood. Other findings included less anxiety, depression, anger and fatigue. There was an increase in blood flow for the cingulate cortex after five days of 20 minutes meditation. The subjects had lower heart rates, decreased skin conductance, decreased breathing rates with increased belly breathing.
Study groups of meditators and non-meditators were given questions with multiple answers (for example, “Name one of the seasons”), then one of the correct answers was flashed on a screen either in a way that could be seen consciously or for only 16 milliseconds, a rate that is too fast to be consciously seen. The meditation group was able to see the subliminal, unconscious, words better. Either they were aware of unconscious material or their concentration was better.
New research with mindfulness meditation shows an improved ability to multitask after the meditation session. The study included simultaneous work with emails, calendars, instant messaging, telephone and word-processing tools to perform common office tasks. They measured speed, accuracy and the extent of switching between tasks. The meditation group showed an ability to stay focused on a task longer with less distraction. They were able to concentrate better, and switch less. They also had decreased stress, increased memory and equal or better productivity
Meditation and Disease
Meditation has now been used to help treat a variety of medical problems. The recent studies include anxiety from cancer, cardiovascular risk in teens, and depression.
An analysis of 22 studies involving 1400 patients from Denmark showed that cancer patients had less anxiety and depression with mindfulness meditation. The result lasted at least six months after the study period.
Cardiovascular Risk in Teens
In a study of 62 black teens with high blood pressure, meditation showed positive effects on their heart. With fifteen minutes of transcendental meditation a day, their heart’s left ventricle became smaller (an enlarged heart is a sign of weakness with an extra workload from the higher blood pressure). The deep rest of the sympathetic nervous system during meditation lowered blood pressure and heart size.
Anxiety and Depression
A new study shows meditation has long-term effects on emotional stability, and decreased anxiety and depression. As in previous studies there was a change in the default network related to daydreaming and self-oriented thought with long-term meditators. This new study of experienced and novice meditators showed weaker synchronization between two regions of the medial prefrontal cortex – the dorsal (cognitive) and the ventral (emotion, self evaluation). This correlates with improvement in depression, because depressed people have hyper connectivity between these two areas. There was also a greater synchronization to the right parietal lobe, which is related to attention.
Physical Exercise, Meditation, Sleep, Daydreaming, and Creativity
The complex relationships between physical exercise, meditation, sleep, and creativity are not yet fully understood, but are intriguing. Physical exercise and meditation are both noted to increase brain regions and increase new learning. Sleep is noted to increase learning and memory as well as creativity. Meditation is also shown to increase creativity. Are these similar or different mechanisms?
Previous studies have shown that sleep during the time of slow waves stimulates increased memory for learned material. This learning could include athletic skills. When exposed to sound and odor cues during sleep the memory of specific locations was increased. Sleeping and dreaming are also correlated with increased creativity. Just recently a tune was played to musicians during slow wave sleep and this enhanced their ability to play the tune when they awoke.
Daydreaming and the Wandering Mind
Daydreaming is important because it allows us to imagine future events, to flesh out ideas, and to create.
A recent study asked subjects to list as many uses as possible for everyday objects such as toothpicks, clothes hangers and bricks. One group then did an undemanding task that encouraged daydreaming. Other groups did focused work, or nothing. The daydreaming group did much better on the next round of creative questioning.
Other studies show that when a person’s mind is wandering they perform better in creativity, association and insight tasks. These include imagination games, original thinking and invention. A recent study showed that people report a wandering mind 47 percent of the time.
Top Athletes, Musicians and Managers
Increased brain coherence is noted in meditation, but is also demonstrated in elite managers, musicians and athletes.
To measure exceptional performances with high brain integration a variety of measures are used. One measure of brain performance is increased coherence of brain waves measured by EEG (see post on Brain Oscillations). This measures how different parts of the brain are in sync with each other and work together. Another EEG measure, that of alpha waves, is related to alertness. The third is a measure of how efficient and effective the brain operates.
By these measures high-level managers, as well as elite professional and amateur musicians showed much more brain integration than less qualified managers and musicians. The most recent study shows that elite athletes also have this high brain integration by the three measures. They also shared a cluster of subjective experienced often referred to as “peak experience,” which includes inner calm, effortlessness, extreme wakefulness, ease of functioning, absence of fear, and a sense of perfection. Some athletes and musicians refer to this feeling as a performance “high”.
It remains for future studies to relate this “peak experience” to meditation states
In Elderly Tai Chi Increases Brain Size, Improves Cognition
Tai Chi is a meditative physical exercise, which is less aerobic than other forms of exercise. Research has already shown that exercise increases brain growth factors to make new cells. Seniors who engaged in Tai Chi three times a week for eight months had increases in brain volume, and better memory and thinking. One of the control groups that used lively discussions instead of the Tai Chi, showed some increase in brain size but less cognitive improvement. The other control group with no intervention had brain shrinkage. Previous trials showed increases in brain with exercise (new brain cells for new learning), increase in memory, but not as much cognitive improvement.
Neuroscience, Meditation, Yoga, and Performance in War
Just as the great American Indian warrior Crazy Horse did many years ago, the new soldier is learning to concentrate his mind for battle using meditative techniques. Martial arts, such as Tai Chi, Karate, and Kung Fu, have always used meditative techniques for superior focus, balance, power and muscular coordination.
Yoga and meditation are now being used in the military to help soldiers become calmer and better decision-makers in order to avoid trauma. Meditation is used before mock training that attempts to simulate the chaos of war scenes. While most military research has been related to brain injury and post traumatic stress, new brain studies, including brain imaging and blood tests for stress markers before and after simulated combat, are being done at the Warfighter Performance Lab to determine stress affects decision-making. Meditation techniques including breathing exercises are being applied to help the soldiers regain a state where good decisions can be made.
The psychological terms used in these military studies include “resiliency”, “psychological hardiness” or “mental toughness”. The new training called Comprehensive Soldier Fitness program increasingly includes these emotional, and psychological elements. Most soldiers have signs of stress, but only 20% have great difficulty in dealing with it. Training in elite forces, like the SEALS, simulate severe states such as near drowning to see who can tolerate this very high level of stress.
The most elite group remaining after very grueling SEAL training shows more activation in the insula, an area related to self-awareness, pain and emotion. The insula also helps relieve stress with awareness.
One early study, called the Trojan Warrior Project, included 10 days of meditation, yoga, and martial arts. After these sessions, soldiers performed much better in biofeedback tests of muscular and neurological reactions to stress. They were also able to learn a foreign language faster, learn complex technical weapons systems better and were better marksman.
Currently, SEALs are using meditation in training, based upon neuroscience data of increased gray matter volume and better synapses in the pre frontal cortex. These brain changes lead to improved ability to have attention control triggers of the amygdala fear responses. The Mindfulness Based Stress Reduction program showed decreased stress, and improvement in concentration, memory, performance of complex tasks, and regaining focus after stress.
Another meditation study for eight weeks, using fMRI, blood markers and saliva markers, showed a better recovery from stress. After the study period soldier’s brains were more likely to resemble the brains of elite SEALS and Olympians.
Previous posts have focused on how attention, and suggestion, as well as meditation, change the brain. The recent understanding is that the brain is much more “plastic” or changeable than previously thought and will change in any way that we choose to exercise it.
In normal function any mental event creates rapid changes in neurons, including building and rebuilding very complex structures almost instantly. (see post).
Meditation is a specific training that builds a “muscle” of mental concentration with increased memory, creativity and cognitive abilities. These new abilities include being able to control the effects of severe stress and include a variety of different subjective internal states.
As mechanisms of these changes are elucidated in the future, hopefully the details of subjective meditative states can be correlated with molecular changes in the brain.